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Tribulus terrestris

puncture vine

Zygophyllaceae

Mediterranean basin, Africa, and southern Asia

Attracts Pollinators Drought Tolerant

SunFull Sun

WaterVery Low · drought-tolerant

Overview

Tribulus terrestris is a low, mat-forming summer annual in the caltrop family, with trailing stems radiating 1-5 feet (0.3-1.5 m) from a central taproot and lying flat against the ground. The leaves are pinnately compound, 1-3 inches (2.5-7 cm) long, divided into 4-8 pairs of small oval leaflets, and covered with soft hairs. Yellow five-petaled flowers about 0.4 inch (10 mm) across open singly in the leaf axils through the warm months. Each flower forms a hard fruit that splits into five woody nutlets, each bearing two to four sharp, rigid spines that can puncture bicycle tires, bare feet, and animal hooves. The plant grows in hot, dry, compacted ground, including roadsides, vacant lots, and cracks in pavement, and roots quickly from a deep taproot that resists pulling. It is naturalized across warm regions worldwide and is treated as a noxious weed in many of them. Foliage can accumulate nitrates and cause photosensitization in grazing sheep, adding a livestock hazard to the mechanical injury from the spined burrs. The spiny seeds remain viable in soil for several years, allowing reinfestation from the seed bank.

Native Range

Native to the warm, dry regions of southern Europe, Africa, and southern Asia around the Mediterranean basin. It grows in sandy and gravelly open ground, and has naturalized across warm parts of the Americas, Australia, and beyond.

Suggested Uses

Tribulus terrestris has no horticultural use and is managed as a weed. It appears in plant references mainly for identification, since its spined seeds injure people, pets, and tires and the foliage poses a risk to grazing livestock.

How to Identify

Identified by prostrate stems spreading flat from a central root, pinnately compound leaves with 4-8 pairs of small leaflets, and yellow five-petaled flowers about 0.4 inch (10 mm) wide. The clearest marker is the fruit: a hard burr splitting into woody nutlets armed with two to four sharp spines. The spined seeds and ground-hugging mat distinguish it from yellow-flowered legumes of similar habitat.

Appearance

Size & Dimensions

Height2" - 6"

Width/Spread1' - 5'

Colors

Flower Colors

yellow

Foliage Colors

green

Bloom Information

Bloom Period

~20 weeks

Spring Summer Fall

Flowers from late spring through fall wherever soil stays warm, with continuous bloom in summer heat. Each flower opens for a single day, and fruits mature within a week or two. Plants can flower and set seed within three to four weeks of germination.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 8.5(Alkaline)

357912

Soil Types

sand rocky clay

Drainagedry

Water & Climate

Water Needs

Very Low

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Tribulus terrestris grows in full sun on poor, dry, compacted soils and tolerates heat and drought through a deep taproot. It needs no cultivation and appears as a weed rather than a planted species. Seedlings emerge after warm-season rains and mature rapidly. Hand-pulling is simplest before the burrs harden, since the spined seeds scatter and cling once mature. Repeated removal over several seasons is needed because buried seed stays viable for years. The plant has no garden water or fertilizer requirements and persists on neglected ground.

Pruning

Pruning is not applicable to this prostrate annual. Clearing whole plants before the fruit hardens limits the spread of the spined seeds. Mowing has little effect because the stems lie flat below the blade.